This proposal is an application to continue postdoctoral study in the neurosciences at the molecular cellular, and systems levels at the California Institute of Technology. The program involves 22 members of the faculty of the Division of Biology, many of whom are also members of the Computational and Neural Systems (CNS) Program. Due to the tremendous growth in neuroscience research at Caltech, we are requesting an increase in the level of the program to fund six trainees per year rather than the four of the past. The program comprises a wide range of areas in the neurosciences such as (1) sensory systems including the auditory, visual and olfactory systems, (2) sensory-motor integration, (3) the cellular and molecular basis of synaptic transmission, (4) neural mechanisms of learning and plasticity, (5) neural development, cell lineage and differentiation, and (6) theoretical neurobiology and computational modeling of neural systems. Future directions of the program will include (1) application of molecular techniques to neurobiology, (2) basic research with medical relevance, and (3) the analysis of complex neural functions from computational and theoretical perspectives, (4) brain imaging in humans, non-human primates, and rodents, and (5) neurophysiological studies using multicellular recordings. The primary mission is to train scientists for fruitful, successful careers in neurobiological research. Trainees hold Ph.D. or M.D. degrees and have daily contact with the research sponsor. The duration of the training period is usually two years with occasional extensions to three years when warranted. Research-related activities such as seminars, journal clubs, and collaborative research through the CNS Program, the Sloan-Swartz Center, the Silvio Conte Neuroscience Center, and the Beckman Institute afford a rich training experience. Also included in the program will be instruction in responsible conduct of research. Special efforts will be made to attract more minority trainees to the program through several approaches, including the extensive involvement of the faculty. The neuroscience laboratories are well equipped and occupy five buildings on the Caltech campus. There are many special resources available to the postdoctoral trainees which include facilities for monoclonal antibody production, transgenic mice study, MRI and optical imaging, primate behavior and electrophysiology, equipment fabrication, computer modeling, electronic circuit design and manufacture, electron microscopy, synthesis and sequencing of proteins and genes, cell sorting, cell culture, and cell electrophysiology. The Biological Sciences Initiative has just been completed, which includes funds for a new biology building, several neuroscience faculty appointment, and new neuroscience facilities.